Voltage regulation is an important aspect of various circuit applications. One type of known voltage regulator is a bandgap-referenced voltage circuit, which generates an output voltage near 1.25V, which is close to the theoretical 1.22 eV bandgap of silicon at 0 K. Bandgap voltage circuits are described at, e.g., U.S. Pat. No. 6,570,437 to Park. Another type of voltage regulator is a low drop-out (LDO) regulator, which is a DC linear voltage regulator that operates with a small input-output differential voltage. LDO regulators are described at, e.g., U.S. Pat. No. 7,030,598 to Dow.
An object of a voltage regulator is to maintain an accurately regulated output voltage notwithstanding variations in current loading of the voltage regulator output and variation of the unregulated input voltage to the voltage regulator. Known voltage regulators are not capable of effectively maintaining a closely regulated output voltage over a wide range of different or changing input voltages. Typically, conventional voltage regulator designs are based on a predetermined nominal specification input voltage and expected load current, within relatively limited tolerances, and generate internal voltages and regulated output power specifications therefrom. Consequently, if the input voltage changes (which may have a variety of reasons, including the desire to accommodate a range of applications), significant time and silicon verification testing may be expended. As a result, the time to market for products may be compromised.